Identification Documents
Identification documents (hereafter “ID documents”) play a critical role in today's society. One example of an ID document is an identification card (“ID card”). ID documents are used on a daily basis—to prove identity, to verify age, to access a secure area, to evidence driving privileges, to cash a check, and so on. Airplane passengers are required to show an ID document during check in, security screening and prior to boarding their flight. In addition, because we live in an ever-evolving cashless society, ID documents are used to make payments, access an automated teller machine (ATM), debit an account, or make a payment, etc.
(For the purposes of this disclosure, ID documents are broadly defined herein, and include, e.g., credit cards, bank cards, phone cards, passports, driver's licenses, network access cards, employee badges, debit cards, security cards, visas, immigration documentation, national ID cards, citizenship cards, social security cards, security badges, certificates, identification cards or documents, voter registration cards, police ID cards, border crossing cards, legal instruments, security clearance badges and cards, gun permits, gift certificates or cards, membership cards or badges, etc., etc. Also, the terms “document,” “card,” “badge” and “documentation” are used interchangeably throughout this patent application.).
Many types of identification cards and documents, such as driving licenses, national or government identification cards, bank cards, credit cards, controlled access cards and smart cards, carry thereon certain items of information which relate to the identity of the bearer. Examples of such information include name, address, birth date, signature and photographic image; the cards or documents may in addition carry other variable or personalized data (i.e., data specific to a particular card or document, for example an employee number) and fixed or invariant data (i.e., data common to a large number of cards, for example the name of an employer). All of the cards described above will hereinafter be generically referred to as “ID documents”.
Identification documents, such as ID cards, having printed background security patterns, designs or logos and identification data personal to the card bearer have been known and are described, for example, in U.S. Pat. No. 3,758,970, issued Sep. 18, 1973 to M. Annenberg; in Great Britain Pat. No. 1,472,581, issued to G. A. O. Gesellschaft Fur Automation Und Organisation mbH, published Mar. 10, 1976; in International Patent Application PCT/GB82/00150, published Nov. 25, 1982 as Publication No. WO 82/04149; in U.S. Pat. No. 4,653,775, issued Mar. 31, 1987 to T. Raphael, et al.; in U.S. Pat. No. 4,738,949, issued Apr. 19, 1988 to G. S. Sethi, et al.; and in U.S. Pat. No. 5,261,987, issued Nov. 16, 1993 to J. W. Luening, et al. All of the aforementioned documents are hereby incorporated by reference.
Printing of Information to Identification Documents
As those skilled in the art will appreciate, information can be printed to identification documents in many ways. Identification documents have been printed using technologies such as dye diffusion thermal transfer (D2T2), inkjet printing, thermal transfer, laser xerography, offset printing, intaglio, Indigo, LaserJet printing, etc.
The above-described printing techniques are not the only methods for printing information on data carriers such as ID documents. Laser beams, for example can be used for marking, writing, bar coding, and engraving many different types of materials, including plastics. Lasers have been used, for example, to mark plastic materials to create indicia such as bar codes, date codes, part numbers, batch codes, and company logos. It will be appreciated that laser engraving or marking generally involves a process of inscribing or engraving a document surface with identification marks, characters, text, tactile marks—including text, patterns, designs (such as decorative or security features), photographs, etc.
One way to laser mark thermoplastic materials involves irradiating a material, such as a thermoplastic, with a laser beam at a given radiation. The area irradiated by the laser absorbs the laser energy and produces heat which causes a visible discoloration in the thermoplastic. The visible discoloration serves as a “mark” or indicator; it will be appreciated that laser beams can be controlled to form patterns of “marks” that can form images, lines, numbers, letters, patterns, and the like. Depending on the type of laser and the type of material used, various types of marks (e.g., dark marks on light backgrounds, light marks on dark backgrounds, colored marks) can be produced. Some types of materials are capable of absorbing laser energy in their native state to a degree such that usable marks are formed. Some types of thermoplastics, such as polyvinylchloride (PVC), acrylonitrile butadiene styrene (ABS), and polyethylene terephthalate (PET), polycarbonate (PC), and polyethylene, may be capable of absorbing some laser energy in their native states, but can be more optimally laser engraved with the addition of one or more additives to be responsive to laser energy. For example, the following commonly assigned patent applications (which are collectively referred to as “laser additive applications”), which are hereby incorporated by reference, describe additives that can enhance the laser engraving process:                Laser Engraving Methods and Compositions, and Articles Having Laser Engraving Thereon (application Ser. No. 10/326,886, filed Dec. 20, 2002, Publication No. 2003-0234286—Inventors Brian Labrec and Robert Jones);        Systems, Compositions, and Methods for Full Color Laser Engraving of ID Documents (application Ser. No. 10/330,034, filed Dec. 24, 2002, Publication No. 2003-0234292—Inventor Robert Jones);        Laser Engraving Methods and Compositions and Articles Having Laser Engraving Thereon (application Ser. No. 10/803,538, filed Mar. 17, 2002, Publication No. 2005-0003297—Inventor Brian Labrec);        Laser Engraving Methods and Compositions and Articles Having Laser Engraving Thereon (Application No. 60/504,352, filed Sep. 19, 2003—Inventors Brian Labrec and Robert Jones); and        Increasing Thermal Conductivity of Host Polymer Used with Laser Engraving Methods and Compositions (application Ser. No. 10/677,092, filed Sep. 30, 2003, Publication No. 2004-0198858).        
For additional background, various laser marking and/or engraving techniques are disclosed, e.g., in U.S. Pat. Nos. 6,022,905, 5,298,922, 5,294,774, 5,215,864 and 4,732,410. Each of these patents is herein incorporated by reference. In addition, U.S. Pat. Nos. 4,816,372, 4,894,110, 5,005,872, 5,977,514, and 6,179,338 describe various implementations for using a laser to print information, and these patents are incorporated herein in their entirety.
Storage of Information on Identification Documents
Issuers of identification documents are continually looking for ways to provide more information to the limited space available on ID documents. As those skilled in the art know, the information on ID documents can be provided in numerous ways, including methods such as printing or laser engraving (e.g., humanly readable form) and/or by providing a machine readable media (e.g., in a magnetic stripe, bar code, radio frequency identification device (RFID), optical write only device (e.g., such as provided by LaserCard), semiconductor chip (e.g., a so-called “smart card” chip). Some types of information, such as digitally watermarked images, can provide information in both human and machine readable form, in a digital watermark or other steganographic encoding embedded in an image, etc.).
Although machine readable devices such as RFIDs, chips, and magnetic media can provide significantly more information storage capability, in a given area, than conventional printing, these devices are not optimal in all circumstances. Some of these devices add significant cost to the ID document and/or reduce the durability and ruggedness of the ID document. In addition, these devices still can take up considerable space on the document.
Bar Codes
Bar codes are one type of machine readable feature that are relatively inexpensive and generally do not reduce document durability; hence, such codes are commonly used. Bar codes generally comprise a series of digits (e.g., a serial number) coded in black and white bars. Some types of so-called “ordinary” bar code are “vertically redundant”, meaning that the same information is repeated vertically. It is in fact a one-dimensional code. The heights of the bars can be truncated without any lose of information. However, the vertical redundancy allows a symbol with printing defects, such as spots or voids, to still be read. The higher the bar heights, the more probability that at least one path along the bar code will be readable.
A two-dimensional (2D) bar code stores information along the height as well as the length of the symbol. In fact, all human alphabets are two-dimensional codes (think of small letters and capital letters). Because both dimensions in 2D contain information, at least some of the vertical redundancy is gone. To prevent misreads and produce an acceptable read rate, techniques such as use of check words can be implemented to help ensure that a read of a 2D bar code is accurate. As use of scanning devices such as movable beam laser scanners and CCD (charge coupled device) scanners has increased, use of 2D bar codes has become more commonplace, especially in identification documents.
Using one dimensional and two dimensional bar codes to provide information in identification documents is known. Traditional black and white bar codes, for example, are capable of encoding a few dozen digits. Because space on many types of identification documents (e.g., driver's licenses) is scarce, however, it is difficult to use bar codes to convey a lot of information about a card bearer, even when using two dimensional bar codes or so-called high definition 2D bar codes.
At least one version of a three dimensional (3D) bar code has been developed, the so-called “bumpy barcode”. Such known types of 3D barcodes comprise a linear barcode (such as a 1D or 2D barcode) embossed on a surface such that the code has a third (height) dimension. Such a 3D barcode can be read by using differences in height, rather than contrast, to distinguish between bars and spaces using a special reader. Examples of usages for 3D barcode are where typical 1D and 2D barcodes cannot be easily placed (such as where printed labels will not adhere) or situations where 1D and/or 2D bar codes can be destroyed by a hostile or abrasive environment. Another application of conventional 3D bar codes is situations where the bar code needs to be painted or coated. 3D bar codes can be painted or coated and still be read.
Known 3D barcodes, however, are not capable of being easily re-written to convey new information. Once provided on a device, the 3D bar code is, effectively, “permanent” unless abraded or shaved off. This can be disadvantageous for use in certain types of identification documents, where information (even variable information—such as address, security clearance, citizenship, etc.) can change. In addition, known 3D bar codes are still limited in the amount of information that they can convey. There exists a need for a new type of 3D data storage that can convey large amounts of information in a given area. There also exists a need for a new type of 3D bar data storage that, at least in some instances, can be capable of being rewritten and/or erased to convey new information.
We have discovered new techniques for providing a type of “3D” data storage, which can be used for conveying multiple levels of information in a given area. Our systems and methods can even be applied to provide new types of 3D bar codes.
In one embodiment, we provide an area of a document with increased capacity for digital data storage. The digital data is stored by varying the color saturation of the individual pixels that make up a portion of a given visibly printed indicia, which indicia can, for example, be a line (curved or straight), border, insignia, bar code, or virtually any other element of an ID document. We assign each range of color saturation a numerical weight that can be associated with a unit of data (e.g., a binary numeral, an ASCII code, etc). This enables us to increase the amount of information that a given group of pixels (or even a single pixel) can convey. For example, instead of a black pixel indicating a first value and a clear space indicating a second value, it is possible to vary the color saturation of the pixel—e.g. using varying shades of gray—to increase the information that can be conveyed in a given pixel. Although some types of color variation of pixels has been proposed previously (see, e.g., U.S. Pat. No. 5,369,261 and U.S. Pat. No. 5,818,032, each of which is incorporated herein in its entirety), as described herein, we have invented innovative systems, methods, and data structures that can provide advantages that were not possible previously.
In one advantageous embodiment, we propose forming the pixels using a laser engraving and/or marking technique, preferably using the technique and materials disclosed in commonly assigned U.S. patent application Ser. No. 10/326,886, which is incorporated by reference herein in its entirety. By forming the pixels using such a laser engraving method, it is possible to precisely control the pixel color saturation to a very high accuracy. Moreover, through careful selection of materials (as will be described herein), it is possible to laser mark a given pixel at a first intensity using a first laser, and then later apply a laser again to that pixel to either darken the pixel further (e.g., by using a YAG laser) or to effectively “whiten” the pixel by removing the information in the pixel (e.g., by using a C02 laser to ablate, etch, or “drill” away the material previously printed by laser). As those skilled in the art will appreciate, laser darkening or “whitening” can even by done to a finished, laminated ID document (assuming that layers overlaying the laser engraved layer are at least partially optically transparent to laser radiation), without necessity of removing any layer of the ID document.
The ability to not only write but also (at least in a limited capacity) to rewrite can be particularly advantageous for identification documents because information on the documents can be updated without having to take apart the document, remove an overlaminate, etc. One skilled in the art will also appreciate that being able to rewrite and/or erase 3D bar coded information can be advantageous in many applications beyond the field of identification documents.
In a second embodiment, we propose encrypting machine readable information such as a digital signature within the 3D barcode.
In one embodiment, we providing an identification document comprising a printable layer, a computer readable data storage element, and a computer readable calibration element. The computer readable data storage element is formed on the printable layer and comprises a plurality of pixels, wherein each pixel has one of a predetermined plurality of colors. The computer readable calibration element is formed on the printable layer and comprises a plurality of pixels and includes information enabling a determination of the pixel size in the computer readable data storage element and also a determination of at least a portion of the predetermined plurality of colors.
In at least one embodiment, the computer readable data storage element and the computer readable calibration element are printed using the same type of printing, such as laser engraving. In one embodiment, at least one of the pixels in the computer readable data storage element is capable of being changed (such as being darkened or cleared) after printing by application of additional laser radiation to the pixel.
In one embodiment, the pixels of the computer readable data storage element are spaced apart from each other by one or more predetermined pixel spacings and where the computer readable data calibration element further comprises information enabling a determination of at least one of the pixel spacings.
In another aspect, we provide a system for providing a printed computer readable data storage element on document, comprising a printable document substrate, a computer readable array of pixels printed on the document substrate and means formed on the printable document substrate for calibrating the intensity of each pixel in the computer readable array of pixels. The system in one embodiment can also include means formed on the printable document substrate for determining the size of each pixel in the computer readable array of pixels. The system in one embodiment can also include means formed on the printable substrate for determining the spacing between the pixels in the computer readable array of pixels.
In still another embodiment, we provide a method for providing a printed computer readable data element to a document, comprising:                printing a first plurality of pixels to a first location on a document, each pixel having a pixel intensity, each pixel intensity associated with a respective piece of data;        printing a second plurality of pixels to second location on the document, the second plurality of pixels comprising at least one pixel associated with each possible pixel intensity;        printing a third plurality of pixels to a third location on the document, the third plurality of pixels comprising a pair of pixels spaced apart and capable of being scanned by a scanner; and.        printing a fourth plurality of pixels to a fourth location on the document, the fourth plurality of pixels spaced a predetermined distance from the second and third pluralities of pixels, the fourth plurality of pixels serving to reference the locations of the second and third pluralities of pixels.        
The first plurality of pixels can be interpreted by first scanning at least one of the second, third, and fourth pluralities of pixels. A reference pixel can be printed to a fourth location on the document, the reference pixel spaced a predetermined distance from the fourth plurality of pixels and from the first plurality of pixels, the reference pixel helping to define at least one predetermined pixel intensity. The pixels can be printed by laser engraving.
One aspect of the invention comprises a method of embedding data in a code readable by machine from a visible light scan of the code. The method comprises pre-printing a two dimensional array of pixels on a substrate. The pixels include at least one calibration pixel, and each have color values. The method selectively alters at least a subset of the pixels by using laser radiation to alter color saturation of the color values of the pixels in the subset relative to the calibration pixel according to digital data values of the code to be embedded in the subset of pixels. This method has been adapted to embed personalized information in pre-printed graphic elements on ID cards.
The foregoing and other features and advantages of the invention will be even more readily apparent from the following Detailed Description, which proceeds with reference to the accompanying drawings and the claims.
Of course, the drawings are not necessarily drawn to scale, with emphasis rather being placed upon illustrating the principles of the invention. In the drawings, like reference numbers indicate like elements or steps. In addition, in the drawings, like reference numbers indicate like elements or steps. Further, throughout this application, certain indicia, information, identification documents, data, etc., may be shown as having a particular cross sectional shape (e.g., rectangular) but that is provided by way of example and illustration only and is not limiting, nor is the shape intended to represent the actual resultant cross sectional shape that occurs during manufacturing of identification documents.